The Tragedy of Hamlet, Prince of Denmark, usually shortened to just Hamlet, was written by Shakespeare sometime between 1599–1602. It is arguably one of his most famous tragedies. The lines from Hamlet's monologue in act three that begin "To be, or not to be …." Have been studied and are widely known even amongst those that are otherwise unfamiliar with Shakespeare's work. Even in Shakespeare's own lifetime, Hamlet would have been performed multiple times and considered remarkably influential. Its appeal has not lessened over time. The play is set in Denmark and follows the prince Hamlet, who seeks revenge upon his uncle Claudius. Claudius murdered his brother, Hamlet's father, in order to seize the throne and also married his wife and Hamlet's mother Gertrude. After Hamlet's sentries and his friend Horatio encounter the ghost of King Hamlet, they vow to tell his son what they have witnessed.